Compressor head cooling system for refrigerator machines



COOPER COMPRESSOR HEAD COOLING SYSTEM Dec. 4, 1951 K. K.

FOR REFRIGERATOR MACHINES Flled May 9, 1947 Ir ventor' Kenneth K.Cooper', by M Z'TEW'A His Attorney.

mama Dec. '4. 951" P UNITED" ST TE comitnssoa HEAD COOLING SYSTEM FOR nnmronaaroa MACHINES KennethlLCooper, Fort Wayne, Ind., assignor to General Electric Company, a corporation of New York Application May 9,1947, Serial no. 746,988

' 12 Claims. (01. 62-1173) My invention relates to refrigerating systems and particularly to arrangements for cooling the heads and discharge valves of reciprocating compressors.

Refrigerating machines employing reciprocating compressors are used in a wide range of applications from relatively high temperature food storage coolers to low temperature testing equipment. In some applications, particularly in the low temperature field, there is a tendency for the exhaust valves and head of the compressor to overheat and it is therefore desirable to provide some arrangement for reducing the temperature of these portions of the compressor. Various arrangements have been proposed for circulating cooling fluid in the vicinity of the compressor head; however, these systems have not been entirely satisfactory and are frequently complicated because of the necessary additional equipment required. Accordingly, it is an object of my invention to provide a refrigerating system including a reciprocating compressor and an improved arrangement for cooling the discharge side of the compressor. I,

It is an other object of my invention to provide a refrigerating system having a reciprocating compressor and utilizing a portion of the condensing capacity for cooling the compressor head and including an improved arrangement for supplying liquid refrigerant for cooling the hot compressed refrigerant as it is discharged from the compressor.

Further objects and advantages of my invention will become apparent as the following description proceeds, and the features of novelty which characterize my invention will be pointed out with-particularity in the claims annexed to and forming a part of this specification. Y

For a better understanding of my invention, reference may be had to the accompanying drawing in which Fig. 1 is a diagrammatic illustration of a refrigerating system embodying my invention; Fig. 2 is an enlarged sectional view of a portion of the compressor of the system illustrated in Fig. 1; and Fig. 3 is a diagrammatic view of a portion of a system similar to Fig. 1 illustrating another embodiment of my invention.

Briefly, the refrigerating system shown on the accompanying drawing, comprises a reciprocating compressor, a water-cooled condenser and an evaporator, all connected in series in a closed refrigerant circuit in the usual manner. Re-

frigerant liquefled in the condenser is collected in a liquid receiver and is supplied to the evaporator under control of a thermostatic expansion valve. In order to cool the discharge valves of the compressor and the hot compressed gas flowing through the head of the compressor, liquid'refrigerant is supplied to the discharge chamber through a conduit arranged to deliver the liquid under influence of the instantaneous differences in pressure existing on the high side of the refrigerating system.

Referring now to the drawing, the refrigerating system illustrated in Fig. 1 comprises a reciprocating compressor I only a portion of which has been illustrated, a condenser 2 cooled by a water-circulating coil 3, and an evaporator 4 connected to receive liquid refrigerant from the condenser through a liquid line 5 under control of a thermostatic expansion valve 6. Refrigerant vaporized in the evaporator 4 is withdrawn through a suction line I and is returned to the compressor. The thermostatic expansion valve includes a temperature 'feeler element or bulb 8 responsive to the temperature of the suction gas and operates in,the usual manner to control the superheat of the vaporized refrigerant withdrawn from the evaporator. The compressor I comprises a cylinder block 9 having cylinders in and II therein within which pistons l2 and I3 are arranged for reciprocation. The cylinders l0 and- II are closed by a valve plate It and a cylinder head I5 is secured to the block together with the plate, suitable gaskets l6 and I! bein provided on either side of the valve plate. 'l'he vaporized refrigerant in the suction line enters a suction passage or chamber l8 and is drawn into the cylinders l0 and H by operation of intake valves I9 and 20, respectively, it being understood that in accordance with the usual practice the pistons l2 and I3 are mounted oppositely so that when one is on the compression stroke the other is on the suction stroke. The compressed refrigerant is delivered into a discharge chamber 2| formed in the head [5 by operation of disk or circular discharge valves 22 and 23 communicating With the cylinders I0 and II, respectively. The valves 22 and 23 are provided with circular backing plates 24 and 25, respectively, which limit the movement of the valves, and'may be constructed, for' example, in accordance with the disclosure of U. S. Letters Patent No. 2,249,480, granted July 15, 1941, in the name of Clifiord W. Leegard. The hot compressed refrigerant flows from the dise charge chamberll through a discharge line 26 to the condenser. 2 where the gas is cooled and liquefied by water or other suitable cooling fluid 3 circulated through the conduit 3. The liquid refrigerant flows to the bottom portion of the condenser, which serves as a liquid receiver, and enters the liquid line 5 through which it is returned to the evaporator. In order to reduce the amount of heat in the compressed gas in the discharge chamber 2|, I have provided a conduit 2! connected at 28 to the liquid line at a point below the level of liquid refrigerant in the receiver portion of the condenser and arranged to conduct liquid refrigerant to fittings 29 and 30 removably secured in the head l5 directly over the discharge valves 22 and 23, re-

spectively. The fittings 29 and 30 are provided with check valves 3| and 32, respectively, which prevent the flow of fluid from the chamber 2| back through the conduit 21 to the liquid line. During the operation of the refrigerating machine, the instantaneous pressures existing in the discharge chamber 2| are sometimes above and sometimes below the average pressure prevailing on the high side of the system, and I have found that by arranging the conduit 21 and check valves 3| and 32 in the manner shown it is possible to employ the difference in instantaneous pressures, which is due to surging in the high side, to produce a flow of refrigerant through the conduit 21 fromthe liquid line. This liquid refrigerant delivered to the chamber 2| is splashed over the discharge valves 22 and 23 and cools the valve assemblies as well as the gas within the chamber. The details of construction of the fittings 29 and 30 are the same and are illustrated in Fig. 2 which shows the fitting 29. This fitting comprises sleeve 33 threaded into the top of the head l5 directly above the valve 22 and coaxial therewith so that the lower end of the sleeve 33 provided with discharge ports 34 is concentric with the valve 22 and retaining member 24. The conduit 21 is secured to the fitting 29 by a suitable nipple 35 which is threaded into the top of the fitting and to which the conduit 21 is secured by-a cap 36 shown in Fig. 1. The check valve 3| is in the form of a disk secured at its center by a .rivet 31 to the sleeve 33 centrally of the circle understood that the valve I9 is provided with suitable apertures (not shown) providing communication between the cylinder I0 and the 7 ports 39. During each period when the instantaneous. pressure existing in the liquid line 5 and fitting 29 is greater than the pressure in the discharge chamber 2|, the check valve 3| is forced downwardly and liquid refrigerant is discharged generally toward the valve 22. This liquid refrigerant is vaporized by the absorption of heat from the parts of the valve assembly and from the hot gas within the chamber 2|, and upon a change in-instantaneouspressure such that the pressure in the discharge chamber 2| is greater than in the fitting 29 the valve 3| is closed and prevents the discharge of refrigerant from the chamber 2| through the fitting 29 and conduit 21.

ates in the same manner. The sleeve 33 is arranged to project well into the chamber2| so The fitting 391s of the same construction as ,the fitting 29 and oper- 4 that the liquid discharged from the fitting enters the chamber near the discharge valve. This provides direct cooling of the valve and prevents overheating.

The amount of liquid refrigerant to be delivered to the chamber 2| through the conduit 21 due to the instantaneous pressure differences is dependent upon the length of time during which the pressure in the conduit is greater than that in the discharge chamber 2| and also upon the resistance characteristics of the conduit and of the check valves, these several factors being taken into consideration in designing the characteristics of the liquid supply circuit for any given installation. The conduit 21 and fittings 29 and 39 are maintained filled with liquid refrigerant since the connection 23 lies in the lower portion 40 of the conduit 5 which lies below the receiver portion of the condenser 2 and acts as a liquid collecting receptacle which it filled with liquid whenever liquid refrigerant is available.

In some refrigerating machines it may be desirable to provide a liquid receiver separate from the condenser, and in Fig. ,3 there is illustrated an arrangement whereby liquid refrigerant may be obtained from the condenser for delivery to the compressor head at all times although the receiver is located remotely from the condenser. The system of Fig. 3 is the same as that of Fig. 1 and corresponding parts have been designated by the same numerals.

In the system of Fig. 3, refrigerant is discharged from the head of the compressor through a conduit 4| and enters a condenser 42 mounted above the level of the compressor head and which is provided with a water cooled coil (not shown) and supplied with a cooling water through a connection 43, water leaving the coil through a connection 44. The refrigerant is cooled and liquefied within the condenser and the liquid flows to a sump 45 formed in the bottom wall of the condenser. The liquid then flows downwardly through a connection 46 to a liquid receiver 41 and thence through the liquid line 5 to the evaporator where it is vaporized and returned to the compressor through the suction line The upper end of the connection 46 opens into the condenser 42 in the upper portion of the sump 45; the sump 45 is thus maintained filled with liquid refrigerant and no liquid fiows to the receiver until there is sufflcient liquid to fill the sump. The liquid line TI for supplying liquid refrigerant to the fittings 29 and 30 is connected to the sump 45 and opens into the sump below the top of the connection 49 so that, whenever liquid refrigerant is available, it flows by gravity to the fittings 29 and 39 and .is available at the fittings for cooling the head of the compressor. The operation of the system of Fig. 3 is thus the same as that of the systern of Fig. 1, liquid refrigerant being supplied to cool the valves and compressor head because of the instantaneous difference in pressure between the refrigerant in the condenser 42 and that in the discharge chamber 2|, the feeding of liquid refriggrant to the fittings being facilitated by the foi ee of gravity,

While I have illustrated particular arrangevalve, 9. cylinder head for said cylinder having a discharge chamber about said valve, a condenser flow of liquid to said discharge chamber being produced by instantaneous differences in pressure,

between the dischargegases in-said chamber and said condenser due to surging, and a check value in said liquid conducting means for preventing back flow of refrigerant from said discharge chamber through said liquid conducting means.

2. In a refrigerating system, a reciprocating compressor havin a cylinder and a discharge valve, a cylinder head for said cylinder having a discharge chamber about said valve, a condenser connected to receive compressed refrigerant from said discharge chamber, means for collecting a l body of refrigerant liquefied by said condenser, a

conduit providing communication between said collecting means and said discharge chamber for conducting liquid refrigerantto said chamber to cool the gas therein, the flow of liquid to saidchamber being produced by instantaneous differences in pressure between the discharge gases in said chamber and in said condenser due to surging, and a check valve in said conduit for preventing back flow of refrigerant from said discharge chamber.

3. In a refrigeratingsystem, a reciprocating compressor having a cylinder and. a discharge valve, a cylinder head for said cylinder having a discharge chamber about said valve, a condenser connected to receive compressed refrigerant from said discharge chamber, means for collecting a body of refrigerant liquefied'by said condenser, a conduit providing communication between said collecting means and said discharge chamber and opening into said chamber adjacent said valve for conducting liquid refrigerant to said chamber, the flow of liquid to said chamber being produced by instantaneous differences in pressure between the discharge gases in said chamber and in said condenser due to surging, and a check valve in said conduit for preventing back flow of refrigerant from said discharge chamber.

4. In a refrigerating system, a reciprocating compressor having a cylinder and a discharge valve, a cylinder head for said cylinder having a. discharge chamber about said valve, a condenser connected to receive compressed refrigerant from said discharge chamber, means for collecting a body of refrigerant liquefied by said condenser, a conduit connecting said liquid collecting means and said chamber and extending through said head and terminating near said discharge valve for conducting liquid refrigerant to said discharge chamber to cool said valve and the compressed gas in said chamber, the flow of liquid to said chamber being produced by instantaneous differences in pressure between the discharge gases in said chamber and in said condenser due to surging, and a check valve in said conduit for preventing back flow of refrigerant from said discharge chamber.

5. In a refrigerating system, a reciprocating compressor having a cylinder anda discharge connected to receive compressed refrigerant from said discharge chamber, means mounted above the level of said cylinder head for collecting a bodyof refrigerant liquefied by said condenser, a conduit connecting said liquid collecting means and said chamber and extending downwardly and opening into said head for conducting liquid refrigerant tosaid discharge chamber to cool said valve and the compressed gas in said chamber,

the flow of liquid to said chamber being produced by instantaneous diifer'ences in pressure between the discharge v.gases'in said chamber and in said condenser due to surging and being facilitated by the force of gravity. and a check valve in said conduit for preventing back flow of refrigerant from said discharge chamber.

6. In a refrigerating system, a reciprocating compressor including a cylinder block having a cylinder therein, a valve plate and cylinder head secured to said block, said cylinder head having a discharge chamber therein adjacent said plate, a discharge valve on said plate within said chamber and of substantially circular configuration, a condenser connected to receive compressed refrigerant from said discharge chamber, means for collecting a body of refrigerant liquefied by said condenser, {a conduit providing communication .between said collecting means and said chamber for conducting liquid refrigerant to said chamber,

, said conduit having its open end substantially concentric with said discharge valve whereby liquid refrigerant is forced through said conduit by the instantaneous differences in pressure between the discharge gases in said chamber and in said condenser due to surging, and a disk check valve mounted at said open end of said conduit for preventing back flow of said refrigerant through said conduit and for directing about said valve liquid refrigerant discharged into said chamber.

7. In a refrigerating system, a reciprocating compressor including a block having a cylinder therein, a valve plate and a cylinder head secured to said block, said plate having a discharge valve therein and said head having a discharge chamber about said valve, a removable conduit fitting mounted in said head and opening above said valve, a check valve on said fitting for preventing discharge of fluid from said chamber through said fitting, a condenser connected to receive compressed refrigerant from said chamber, means for collecting a body of refrigerant liquefied by said condenser, and a conduit connecting said collecting means and said fitting whereby a flow of liquid refrigerant to said chamber is produced by instantaneous differences in pressure between the discharge gases in said chamber and in said condenser due to surging, the liquid refrigerant flowing through said fitting entering said chamber and cooling the gas therein.

8. In a refrigerating system, a reciprocating compressor having intake and discharge chambers, a condenser connected to receive compressed refrigerant from said compressor, said condenser including a liquid receiver, liquid collecting means below said receiver, a conduit connecting said collecting means and said discharge chamber for conducting liquid refrigerant to said chamber to cool the gas therein, the flow of liquid to said discharge chamber being produced by instantaneous differences in pressure between the discharge gases in said chamber and 7 v said condenser, and a check valve in said conduit for preventing back flow of refrigerant from said chamber. 7

9. In a refrigerating system, a reciprocating compressor having intake and discharge chambars, a condenser, a refrigerant evaporator, means for connecting said compressor and condenser and evaporator in a closed refrigerant circuit, said circuit including a liquid receiver connected in said circuit adjacent said condenser, and a liquid line connected between the bottom of said receiver and said evaporator, a conduit connecting said discharge chamber and said liquid line for conducting liquid refrigerant to said discharge chamber in accordance with instantaneous diiferences in pressure between the discharge gases in said chamber and in said condenser, and a check valve in said conduit for preventing back flow of refrigerant from said chamber.

10. In a refrigerating system, a reciprocating compressor having a discharge chamber, a condenser connected to receive compressed refrigerant from said compressor andhaving a liquid collecting sump therein, a liquid receiver arranged in communication with the upper portion of said sump to receive liquid from said condenser, a conduit connecting a lower portion of said sump and said discharge chamber whereby liquid refrigerant is delivered to said discharge chamber under the instantaneous differences in pressure between the discharge gases in said chamber and in said condenser, and a check valve in said conduit for preventing back flow of refrigerant from said discharge chamber to said sump.

11. A reciprocating compressor for refriger- 8 head providing a discharge chamber about said valve, means including a fluid conducting fltting secured in said head and having a port opening within said chamber for supplying cooling fluid to said valve, and a check valve in said fitting for preventing flow of fluid from said chamber through said fitting.

12. A reciprocating compressor for refrigerat- -ing systems including a cylinder block having a cylinder therein, a cylinder head, a discharge valve between said cylinder and said head, said head providing a discharge chamber about said valve, means including a fluid conducting fitting secured-in said head and having a port opening within said chamber near said valve for supplying cooling fluid to said valve, and a check valve comprising a flexible disk secured to the end of said fitting and covering said port for preventing flow of fluid from said chamber through said fitting.

KENNETH K. COOPER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

